Frequencies for first 10,000 rows of rx4v1c1 variable in nhamcsed2006 dataset :

   for rx4, level 1 of multum |
             drug category #1 |      Freq.     Percent        Cum.
------------------------------+-----------------------------------
              anti-infectives |        165        1.65        1.65
              antineoplastics |          2        0.02        1.67
        cardiovascular agents |         97        0.97        2.64
central nervous system agents |        532        5.32        7.96
        coagulation modifiers |         22        0.22        8.18
      gastrointestinal agents |         79        0.79        8.97
                     hormones |         55        0.55        9.52
         miscellaneous agents |         32        0.32        9.84
         nutritional products |         58        0.58       10.42
           respiratory agents |        124        1.24       11.66
               topical agents |         25        0.25       11.91
        alternative medicines |          1        0.01       11.92
     psychotherapeutic agents |          6        0.06       11.98
         immunological agents |         11        0.11       12.09
            radiologic agents |          1        0.01       12.10
             metabolic agents |         16        0.16       12.26
           pharmaceutical aid |          2        0.02       12.28
                            . |      8,772       87.72      100.00
------------------------------+-----------------------------------
                        Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016